As devices analyzing object components contained in biological samples such as blood, automated analyzers that measure a quantity of light of transmitted light or scattered light with a single wavelength or a plurality of wavelengths obtained by radiating light from light sources to a reaction liquid which is an analyzer and in which a sample and a reagent are mixed are widely used.
As automated analyzers, there are devices for biochemical analysis performing quantitative and qualitative analysis of object components in biological samples and devices for blood coagulation analysis measuring coagulability of blood which is a sample, for example, in fields of biochemical examination or hematologic examination.
In either analysis, quantitative or qualitative analysis of an object component is performed by ascertaining the quantity of light from a light source or a change in the wavelength with a photodetector. When light other than light from a light source, such as light from outside is incident on the photodetector, since it is no longer possible to accurately measure the quantity of light and the change in the wavelength, it is also no longer possible to accurately measure the analysis of the object component.
In regard to a technology for preventing light from outside from entering the photodetector, PTL 1 discloses a technology for protecting a light-receiving element from excessive light when two light shielding mechanisms having opening parts are provided and a measurement vessel is mounted on a detector.
PTL 2 discloses a constitution including: a light shielding member that is provided below a test tube installation position, shields light incident on a detector in a state other than photometry, that is, in a state in which a test tube is not provided in a measurement chamber, moves down while pushing the test tube when the test tube is inserted into the measurement chamber, and enables light from a measurement target to be incident on the detector; and a cover that is provided above the test tube at the time of measurement and covers an opening part.
PLT 3 discloses a technology for providing a shutter mechanism that shields a gap between a measurement part on a cuvette mounting position of the measurement part and a reagent dispensation mechanism and hiding the cuvette mounting position by the shutter mechanism when the reagent dispensation mechanism reciprocates on the measurement part.